Influence of retino-tectal innervation on cell proliferation and cell migration in the embryonic teleost tectum

ABSTRACT The influence of retino-tectal innervation on cell proliferation and cell migration in the optic tectum of the embryonic teleosts, Brachydanio rerio and Astyanax mexicanus, was investigated in a combined autoradiographic and experimental embryological study. Unilateral eye Anlage removal was the method used to compare development of the affected non-optic-innervated tectum with that of its normal opposite innervated tectum. The amount of mitosis as estimated by [3H]thymidine incorporation was not stimulated by retino-tectal innervation. Likewise no increase in cell number was found in the innervated tectum. Cell migration and differentiation in the marginal zone was enhanced by retino-tectal innervation. Conflicting results concerning proliferation, migration and differentiation in different species are explained by differences in time of ingrowth of the optic nerves and their depth of penetration into the tectum.